1. Field of the Invention
The present invention relates to a connector structure, and more particularly, to a connector structure applied for high frequency signal transmission.
2. Description of the Prior Art
With rapid development of electronic industries and multimedia application, data transmission between electrical appliances is increasing gradually. Besides expanding transmission bandwidth, the current trend is towards to utilize electrical connectors with high frequency signal transmission. The need for standardization in computer related interfaces, as well as the need for high-speed communication interfaces, leads to the development of the universal serial bus (USB) interface. More recently, the USB Type-C connector has emerged as a USB-type connector having a relatively compact size, ultrahigh data transmission speed, and being configured so that the USB Type-C connector can be coupled without regard to plug orientation and/or cable direction, for extensive applications on different electronic devices. Furthermore, because super speed signal terminals of the USB type-C connector, when operating, other electronic components might be interfered by the electromagnetic waves, electromagnetic interference (EMI) proof function is necessary and usually achieved by grounding.
Please refer to FIG. 1. FIG. 1 is a sectional diagram of a conventional USB Type-C connector 1 in the prior art. The USB Type-C connector 1 includes a plastic housing 11, a shell 12, upper terminals 13, lower terminals 14, and a grounding plate 15. The plastic housing 11 includes a base portion 111 and a tongue portion 112 extending from the base portion 111. The grounding plate 15 is embedded inside the tongue portion 112, and the upper terminals 13 and the lower terminals 14 are respectively disposed on an upper surface and a lower surface of the tongue portion 112. The shell 12 surrounds the tongue portion 112 to form a jack 16. The electromagnetic interference between the upper terminals 13 and the lower terminals 14 can be prevented by the grounding plate 15, so as to achieve stable high frequency signal transmission. A relative position and a pitch of an upper pin 131 of the upper terminal 13 and a lower pin 141 of the lower terminal 14 have to cooperate with layout of a circuit board whereon the USB Type-C connector 1 is installed.
A height difference between the jack 16 of the USB Type-C connector 1 and the circuit board needs to be adjusted due to limitation of mechanical space inside the electrical appliances. It is a common practice to increase lengths of an upper vertical portion 132 of the upper terminal 13 and a lower vertical portion 142 of the lower terminal 14 and to heighten the base portion 111 of the plastic housing 11, so as to increase the height difference between the jack 16 of the USB Type-C connector 1 and the circuit board. However, it brings variation and instability of characteristic impedance of front and rear ends of the USB Type-C connector 1, which affects efficiency of high frequency signal transmission.